1. Field of the Invention
The present invention relates to an output circuit which is suitable for a logic circuit included in a semiconductor device or the like.
2. Description of the Related Art
The inventors of the present application know that the logic circuit used in an IC or LSI has its particular I/O logic level (positive or negative logic), that is, the I/O logic level depends on each kind of logic circuit. The known logic circuit is required to convert the positive logic to the negative logic or vice versa for connecting the circuits such as ICs or LSIs. To meet the requirement, the LSI provides some output pins with the corresponding additional circuits for changing the output logic. For example, a register is provided inside of the LSI so that the register may be initialized for determining if the logic is positive or negative.
That is, the known logic changing system utilizing a register needs to initialize the register. This initialization entails an additional component such as a circuit or a program. This has been a great disadvantage.